Weld insert and refractory anchor

ABSTRACT

A protective refractory member for protecting heat-absorptive elements in a high-temperature furnace comprises a refractory shape, an interconnected, reticulated metal mesh embedded within the shape and positioned substantially adjacent an inner surface of the shape and at least one opening extending through a thickness of the shape and through the mesh. A tubular insert is located within the opening and is welded to the spirals which define the mesh. Both the insert and certain of the spirals engage the heat-absorptive element and the insert is welded to the element to retain the member thereto.

FIELD OF THE INVENTION

This invention relates to furnace insulation systems, and moreparticularly, to a protective refractory member for attachment to aheatabsorptive element in a high-temperature furnace such as a reheatfurnace or electric arc furnace.

BACKGROUND OF THE INVENTION

A number of different furnace system are utilized in modern day furnacesto protect the metal structures contained therein. For example,water-cooled pipes and support structures in reheat furnaces areprotected by lengths of refractory shapes positioned in end-to-endrelationship and connected to the pipe or structure to be protected.Other structures in a reheat furnace are often water-cooled and must beprotected. Typical examples are water-cooled box beams and water-cooleddoor lintels.

Some applications present expansive surface areas which must be coveredwith protective refractory members. One such application is thewater-cooled panels which make up the wall structure and roof above themelt line in an electric arc furnace.

It is known to use a weld insert within a protective refractory member,which weld insert is welded to the underlying metal member to beprotected. The present inserts are inadequately retained within therefractory member and are subjected to deterioration from concentratedheat. A need remains for a weld insert which is better anchored withinthe refractory and an insert which is better cooled to preventdeterioration.

SUMMARY OF THE INVENTION

Our weld insert and refractory anchor is securely retained within arefractory member, thus permitting the refractory member to be used inapplications which are subjected to high and cyclic temperatures, aswell as repetitive vibrations and the like. The weld insert refractoryanchor is further protected from rapid deterioration through a series ofcontacts with the heat-absorptive element being protected. Thesecontacts include the insert and the reinforcement which is welded to theinsert.

This protective refractory member comprises a refractory shape having aninterconnected, reticulated metal mesh defined by a plurality of spiralsembedded within the shape and positioned substantially adjacent an innersurface of the shape. At least one opening extends through the thicknessof the shape and through a spiral and a tubular insert is located withinthe opening adjacent the inner surface. The tubular insert is welded tothe spiral which anchors the insert within the shape and the shape issubsequently welded to a heat-absorptive element by welding the insertto the element.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a flat shape with our weld insert andrefractory anchors;

FIG. 2 is a plan view of the insert welded to the reticulated metalmesh;

FIG. 3 is a sectional view taken along line 4--4 of FIG. 4 showing theattachment of the weld insert to a metal substrate; and

FIG. 4 is a perspective view of a water-cooled side wall panel used inan electric arc furnace.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The protective refractory member, generally designated 10, can be of anyparticular shape and a flat refractory protective member for use atelevated temperatures is illustrated in FIG. 1. Four clear-throughopenings 12 through the shape 10 permit attachment of the shape 10 to anunderlying metal substrate through conventional welding techniques.

The weld insert and refractory anchor are best seen in FIGS. 2 and 3. Areticulated metal mesh 16 is embedded within the shape 10 and ispositioned along the inner surface 30 which abuts the heat-absorptiveelement 28 to be protected. Mesh 16 is formed of a pair of bent wiresinterconnected to define a plurality of spirals 18, FIG. 2. The weldinsert 14, which is a tubular member, is positioned within a spiral 18at the inner surface 30 and is spot-welded (20 and 22) at diametricallyopposed positions to the two different wires which make up the spiral inthe first instance. Both the insert 14 and at least some of the mesh areexposed along the inner surface 30 of the shape 10 so as to be in directengagement with the metal substrate 28. Weld insert 14 is of lesseraxial extent than the shape 10 so that the opening 12 in a typicalcastable refractory is actually defined by two different cross sections,with the smaller cross section being the inside diameter of the insert.In other refractories such as phosbonded products the opening 12 is thesame as the inside diameter of the insert.

The shape 10 is positioned against the heat-absorptive metal element 28and a weld rod is inserted into the opening 12 and into the tubularinsert 14 and the tubular insert 14 is welded to the metal substrate tohold the shape thereto. This weld may go around the inside perimeter ofthe insert 14 or, as shown, may be a fillet weld 24 or a pair of suchwelds.

The size of the opening 12 through the refractory and the insidediameter of the insert 12 are sufficiently large to allow the necessaryangle for the weld rod so that a good structural weld is obtained.

The combination of the reticulated metal mesh in the form of spiralswelded to the insert provides a strong anchor system. The fact that boththe insert and at least certain of the spirals which are welded to theinsert engage the cool, metal surface to be protected prevents the rapiddeterioration of the insert and provides a better over-all insulation ofthe heat-absorptive member.

A typical application is illustrated in FIG. 4 in which a water-cooledmetal panel 32 having inlet and outlet pipes 36 is protected by aplurality of refractory shapes 10. Such a water-cooled panel is used asside walls in electric arc furnaces above the slag line. Shape 10 iswelded to the water-cooled metal panel 32 through the two openings 12.After welding has taken place, a refractory filler is used to close ineach opening 12. The particular panel illustrated in FIG. 4 has a slightcurvature to it, although a plurality of small flat shapes can be usedto protect the ever-so-slight curvature. Of course, it will berecognized that the shape itself could be curved in the same manner asthe underlying substrate and the weld insert and refractory anchor wouldbe employed in the same manner.

A typical shape will be made of an alumina refractory which canwithstand the particular elevated temperature of the intendedapplication. The spirals will be formed of 314 stainless steel having a0.120 inch diameter (standard 11 gauge). The spirals are formed by twointerconnected wires having 51/2 turns for every 11 inches of length.The spirals form an opening to accommodate a 11/2 inch diameter insert.The insert, which is made out of a standard stainless steel pipe, suchas 304 stainless, is 3/4 inch high. Both the wire and insert may be madeof other weldable metals such as carbon steel or corten. The height ofthe insert varies depending on the density of the refractory, with alonger insert being feasible in a less dense, better insulated shape.Generally, the insert will be on the order of 1/2 the thickness of theshape but 3/4 inch inserts have also been used with 2 inch thick shapes.

The number of inserts per shape depends primarily on the size of therefractory member, although applications in which the refractory issubjected to severe vibration, may also require more inserts. Presently,flat refractory members 9"×9" and 6"×9" require two inserts per shape.Shapes of a foot square or more may require more inserts although fourinserts per shape is more than adequate for the larger shapes. Two ormore spaced inserts can also be utilized along a single length ofspirals to reduce handling in manufacture and provide continuity.

It is also possible to use a single wire bend formed into half spiralsin conjunction with a weld insert. Such an arrangement finds particularapplication with smaller shapes.

We claim:
 1. A protective refractory member for protecting aheat-absorptive element in a high-temperature furnace comprising arefractory shape, an interconnected reticulated metal mesh embeddedwithin the shape positioned substantially adjacent an inner surface ofthe shape, at least one opening extending through a thickness of saidshape and through said mesh to form a clear-through, uninterruptedpassageway, a tubular insert located within the passageway and extendingto said inner surface, said insert being welded to said reticulatedmetal mesh, said member adapted for attachment to an element by engagingsaid inner surface to an element and welding said insert thereto.
 2. Themember of claim 1, said member being substantially flat.
 3. The memberof claim 2, said mesh being defined by a plurality of spirals, saidinsert fitting within a spiral and welded thereto.
 4. The member ofclaim 2, said insert having an axial extent less than a thickness ofsaid member.
 5. In combination, a heat-absorptive element in ahigh-temperature furnace and a plurality of protective refractorymembers positioned in side-by-side relationship to substantially coversaid element, each member including an interconnected, reticulated metalmesh in the form of a plurality of spirals embedded within the memberand positioned substantially adjacent an element contacting surface ofsaid member so that at least certain of said spirals engage saidelement, at least two spaced-apart openings, each extending axiallythrough a thickness of said member and through a spiral, a tubularinsert located in each opening at said contacting surface in engagementwith said element, said insert being welded to said spiral and to saidelement to retain said member thereto.
 6. The combination of claim 5,said members being substantially flat.
 7. The member of claim 5, saidinsert having an axial extent less than a thickness of said member. 8.The member of claim 5, said insert and said mesh being selected from thegroup of stainless steel, carbon steel, and corten.
 9. The member ofclaim 5, said spirals formed by a pair of interconnected, bent-formedwires having on the order of 51/2 turns for every 11 inches of length.